1. Field of the Invention
The present invention relates to an electrochromic device, more specifically, to an electrochromic device in which an electrochromic coating layer coated with an electrochromic material is formed so that uniform discoloration and decolorization can be performed.
2. Description of the Related Arts
Electrochromism is a phenomenon in which a color is reversibly changed by the direction of an electric field when a voltage is applied. An electrochromic material is a material, an optical property of which can be reversibly changed by an electrochemical redox reaction having the electrochromism property. The electrochromic material is not colored when an electrical signal is not applied from the outside, but it is colored when the electrical signal is applied. On the contrary to this, when the electrical signal is not applied from the outside, the electrochromic material is colored, but when the electrical signal is applied, the electrochromic material is not colored.
An electrochromic device, which is a device using a phenomenon in which the light transmission of an electrochromic material is changed by an electrochemical redox reaction, has been used for adjusting the light transmission or reflectance of a window glass for building or a mirror for automobiles. Recently, as the electrochromic device has been known to have an infrared cutoff effect as well as a color variation in a visible ray area, it has been receiving a great deal of attention with regard to the possibility of application as an energy-saving type product.
In particular, the electrochromic mirror (ECM) is a mirror for stably protecting a driver's field of vision by providing a variation in reflectance depending upon discoloration of the mirror at the same time as automatically sensing the strong beam of a car reflected from a car mirror in the daytime or at night.
FIG. 1 is a view schematically illustrating the structure of a conventional electrochromic device. Referring to the drawing, the conventional electrochromic device is configured such that a first substrate 10 and a second substrate 20 opposed to each other are disposed to be spaced apart from each other, an electrode 30 and a reflection layer 40 are formed on facing surfaces of the first and second transparent substrates 10, 20, respectively, a space is formed between the electrode 30 and the reflection layer 40 using a sealant 50, and an electrochromic material layer 60 is formed by injecting a liquid discoloration material and an electrolyte into the formed space. Also, first and second electrode connection units 70, 80 are provided on one end of the first substrate 10 and electrode 30, and one end of the second substrate 20 and the reflection layer 40, respectively. The conventional electrochromic device, particularly an electrochromic mirror, functions to protect a driver's field of vision by applying an electrochromic material in a liquid state to reduce the reflectance of light.
However, in order to maintain an electrochromic state of the electrochromic material in the liquid state, a voltage should be continuously applied. Thus, it is problematic in that high power consumption is required, and a reaction speed is slow upon decolorization. Furthermore, the electrochromic material in the liquid state is problematic in that uniform discoloration is not performed upon discoloration.